Marine Mammal Species Research Articles

The Arctic and the future Arctic? Soundscapes and marine mammal communities on the east and west sides of Svalbard characterized through acoustic data

The Svalbard Archipelago, Norway, is warming rapidly, resulting in environmental change that is likely already affecting the underwater soundscape, a critical habitat feature for marine mammals. Baseline information about current sound levels is needed to monitor future changes. Fixed-location recorders were used in this study to characterize the soundscape and study the occurrence and phenology of marine mammals at two locations within Svalbard. Kongsfjorden (2017-2018), on the west coast, has already undergone vast environmental change, whereas M2 (2019-2020), on the east coast, remains more Arctic. The results of the study reveal that the soundscapes and species assemblages differed markedly west vs east. In the west, Arctic species were detected from winter to summer and migrant marine mammal species were detected occasionally through the autumn. In the east, Arctic species were detected constantly on an almost year-round basis, and a few migrant species were detected during summer. Vessels were detected more often in the west than in the east, in accordance with AIS traffic data that indicated more boat traffic in Kongsfjorden in the west than in the east of the archipelago. In terms of soundscapes, geophonies (wind, ice) were the main factors determining the sound energy at both locations. Kongsfjorden’s soundscape was characterized by glacier-melt sounds with moderate levels of anthropogenic noise and some biophonies (marine mammals). At M2, sea-ice noises shaped the soundscape, which was otherwise dominated by biophonies from Arctic marine mammals. At the east coast site there was little impact from anthropophonies (vessels). This study provides information on Svalbard’s current underwater soundscape, which is likely to be transformed in the future due to ongoing climate change, with the west coast reflecting future conditions in many Arctic regions if ship-traffic is not regulated.

Survival improvements of marine mammals in zoological institutions mirror historical advances in human longevity.

An intense public debate has fuelled governmental bans on marine mammals held in zoological institutions. The debate rests on the assumption that survival in zoological institutions has been and remains lower than in the wild, albeit the scientific evidence in support of this notion is equivocal. Here, we used statistical methods previously applied to assess historical improvements in human lifespan and data on 8864 individuals of four marine mammal species (harbour seal, Phoca vitulina; California sea lion, Zalophus californianus; polar bear, Ursus maritimus; common bottlenose dolphin, Tursiops truncatus) held in zoos from 1829 to 2020. We found that life expectancy increased up to 3.40 times, and first-year mortality declined up to 31%, during the last century in zoos. Moreover, the life expectancy of animals in zoos is currently 1.65-3.55 times longer than their wild counterparts. Like humans, these improvements have occurred concurrently with advances in management practices, crucial for population welfare. Science-based decisions will help effective legislative changes and ensure better implementation of animal care.

The Hypothalamus of the Beaked Whales: The Paraventricular, Supraoptic, and Suprachiasmatic Nuclei.

The hypothalamus is the body's control coordinating center. It is responsible for maintaining the body's homeostasis by directly influencing the autonomic nervous system or managing hormones. Beaked whales are the longest divers among cetaceans and their brains are rarely available for study. Complete hypothalamic samples from a female Cuvier's beaked whale and a male Blainville's beaked whale were processed to investigate the paraventricular (PVN) and supraoptic (SON) nuclei, using immunohistochemical staining against vasopressin. The PVN occupied the preoptic region, where it reached its maximum size, and then regressed in the anterior or suprachiasmatic region. The SON was located from the preoptic to the tuberal hypothalamic region, encompassing the optical structures. It was composed of a retrochiasmatic region (SONr), which bordered and infiltrated the optic tracts, and a principal region (SONp), positioned more medially and dorsally. A third vasopressin-positive nucleus was also detected, i.e., the suprachiasmatic nucleus (SCN), which marked the end of the SON. This is the first description of the aforementioned nuclei in beaked whales-and in any marine mammals-as well as their rostro-caudal extent and immunoreactivity. Moreover, the SCN has been recognized for the first time in any marine mammal species.

Passive ocean acoustic waveguide remote sensing of vocalization behavior and spatial distribution of diverse marine mammal species in the Norwegian and Barents Sea

Leveraging data acquired using a 160-element coherent hydrophone array deployed in the Norwegian and Barents Seas during spring 2014, and the passive ocean acoustic waveguide remote sensing (POAWRS) technique is employed to enable instantaneous wide-area monitoring of marine mammal vocalizations over expanses exceeding 100 km in diameter. The vocalization behavior of diverse marine mammal species including Fin, Humpback, Minke, Sperm, and Beluga whales are analyzed, quantifying time-frequency characteristics and call patterns from their vocalization signals present in high-resolution beamformed power spectrograms. Previously developed automatic detection and machine learning algorithms are employed for clustering and classification of underwater acoustic events, facilitating the subsequent manual audio-visual inspection of whale calls. Bearing-time trajectories of repetitive species-specific vocalizations signals are utilized to estimate locations of the whale calls and hence their temporo-spatial distributions. Through comparative studies, we assess the presence and abundance of marine mammal species-specific vocalization signals in three distinct coastal regions off Norway, namely, Alesund, Lofoten, and Northern Finmark. In addition, we investigate correspondences of marine mammal distributions with concurrently imaged instantaneous wide-area fish distributions from distinct fish species to elucidate potential predator-prey interactions and habitat preferences.

Vulnerability to climate change of United States marine mammal stocks in the western North Atlantic, Gulf of Mexico, and Caribbean.

Climate change and climate variability are affecting marine mammal species and these impacts are projected to continue in the coming decades. Vulnerability assessments provide a framework for evaluating climate impacts over a broad range of species using currently available information. We conducted a trait-based climate vulnerability assessment using expert elicitation for 108 marine mammal stocks and stock groups in the western North Atlantic, Gulf of Mexico, and Caribbean Sea. Our approach combined the exposure (projected change in environmental conditions) and sensitivity (ability to tolerate and adapt to changing conditions) of marine mammal stocks to estimate vulnerability to climate change, and categorize stocks with a vulnerability index. The climate vulnerability score was very high for 44% (n = 47) of these stocks, high for 29% (n = 31), moderate for 20% (n = 22), and low for 7% (n = 8). The majority of stocks (n = 78; 72%) scored very high exposure, whereas 24% (n = 26) scored high, and 4% (n = 4) scored moderate. The sensitivity score was very high for 33% (n = 36) of these stocks, high for 18% (n = 19), moderate for 34% (n = 37), and low for 15% (n = 16). Vulnerability results were summarized for stocks in five taxonomic groups: pinnipeds (n = 4; 25% high, 75% moderate), mysticetes (n = 7; 29% very high, 57% high, 14% moderate), ziphiids (n = 8; 13% very high, 50% high, 38% moderate), delphinids (n = 84; 52% very high, 23% high, 15% moderate, 10% low), and other odontocetes (n = 5; 60% high, 40% moderate). Factors including temperature, ocean pH, and dissolved oxygen were the primary drivers of high climate exposure, with effects mediated through prey and habitat parameters. We quantified sources of uncertainty by bootstrapping vulnerability scores, conducting leave-one-out analyses of individual attributes and individual scorers, and through scoring data quality for each attribute. These results provide information for researchers, managers, and the public on marine mammal responses to climate change to enhance the development of more effective marine mammal management, restoration, and conservation activities that address current and future environmental variation and biological responses due to climate change.

Highly pathogenic avian influenza A (H5N1) in marine mammals and seabirds in Peru

Highly pathogenic avian influenza (HPAI) A/H5N1 viruses (lineage 2.3.4.4b) are rapidly invading the Americas, threatening wildlife, poultry, and potentially evolving into the next global pandemic. In November 2022 HPAI arrived in Peru, triggering massive pelican and sea lion die-offs. We report genomic characterization of HPAI/H5N1 in five species of marine mammals and seabirds (dolphins, sea lions, sanderlings, pelicans and cormorants). Peruvian viruses belong to lineage 2.3.4.4b, but they are 4:4 reassortants where 4 genomic segments (PA, HA, NA and MP) position within the Eurasian lineage that initially entered North America from Eurasia, while the other 4 genomic segments (PB2, PB1, NP and NS) position within the American lineage (clade C) that circulated in North America. These viruses are rapidly accruing mutations, including mutations of concern, that warrant further examination and highlight an urgent need for active local surveillance to manage outbreaks and limit spillover into other species, including humans.

Seasonal variation in trophic structure and community niche dynamics of an Arctic coastal community of marine vertebrates

Temporal variation in food web structure is widespread among highly seasonal environments, such as the Arctic, and is driven by changes in resource availability. Variation in resource availability can lead to species differences in diet composition, isotopic niche width, and trophic position (TP) across seasons. Here, we used tissue samples that represent two distinct turnover rates for diet (liver = shorter term, muscle = longer term) from 18 fish and three marine mammal species to investigate seasonal (i) variation in TPs within the Southampton Island marine ecosystem of Hudson Bay, (ii) variation in consumer isotopic niche width within this part of the food web, and (iii) variation in community niche dynamics among a fish and marine mammal community using stable carbon (δ13C) and nitrogen (δ15N) isotope analyses. Many zooplanktivores and piscivores increased in TP in summer (i.e., shorter-term turnover period), whereas benthic feeders dependent on ice-obligate prey decreased in TP. Most isotopic niche widths and community metrics (δ15N range, total ellipse area, mean centroid distance) were higher in liver than muscle. Our findings demonstrate seasonal changes in TPs, which suggests that Arctic communities may be differentially affected by longer ice-free periods and earlier onset of primary production due to accelerated climate change.

Halal Perspectives on Collagen-Based Biomaterials in Tissue Engineering Applications

The halal status of biomedical applications has recently been under intense demand due to the utilization of critical ingredients in developing the products. One of the disciplines in biomedical applications, uses various types of biomaterials is tissue engineering. Due to its promising biocompatibility, low antigenicity, and biodegradability, collagen is well known and frequently employed as biomaterials for tissue engineering applications. Most of collagen come from sources including bovine, porcine, marine, and other mammal species. These huge sources end up being one of the most important factors in determining the halal status. Therefore, the purpose of this review is to emphasize collagen's application as biomaterials from the halal standpoint. Additionally, several collagen sources and their status as halal biomaterials for neural, skin, bone, and tissue engineering were covered, with an emphasis on the potential implementation of collagen from halal sources.

Microplastics in marine mammal blubber, melon, & other tissues: Evidence of translocation

Marine mammals consume large quantities of microplastic particles, likely via trophic transfer (i.e., through prey who have consumed plastic) and direct consumption from seawater or sediment. Microplastics have been found in the stomachs, gastro-intestinal tracts, and feces of cetaceans and pinnipeds. Translocation of ingested microplastics has been documented in other organs of several aquatic species, but has not been examined in marine mammals. Marine mammals have highly specialized lipid-rich tissues which may increase susceptibility to lipophilic microplastics. Here we demonstrate the occurrence of microplastics, ranging in size, mass concentration, and particle count concentration from 24.4 μm – 1387 μm, 0.59 μg/g – 25.20 μg/g, and 0.04 – 0.39 particles/g, respectively, in four tissues (acoustic fat pad, blubber, lung, & melon) from twelve marine mammal species inclusive of mysticetes, odontocetes, and phocids. Twenty-two individuals were examined for microplastics using a combination of Raman spectroscopy and pyrolysis gas chromatography with mass spectrometry. Overall, 68% of individuals had at least one microplastic particle in at least one of the four tissue types, with the most common polymer and shape observed being polyethylene and fibers, respectively. These findings suggest some proportion of ingested microplastics translocate throughout marine mammal bodies posing an exposure risk to both marine mammals and people. For people, exposure could be directly through consumption for those who rely on marine mammals as food and indirectly to peoples globally who consume the same prey resources as marine mammals. Some individuals examined represent samples obtained over two decades ago, suggesting that this process, and thus exposure risk, has occurred for some time.

Input compensation of dolphin and sea lion auditory brainstem responses using frequency-modulated up-chirps.

Frequency-modulated "chirp" stimuli that offset cochlear dispersion (i.e., input compensation) have shown promise for increasing auditory brainstem response (ABR) amplitudes relative to traditional sound stimuli. To enhance ABR methods with marine mammal species known or suspected to have low ABR signal-to-noise ratios, the present study examined the effects of broadband chirp sweep rate and level on ABR amplitude in bottlenose dolphins and California sea lions. "Optimal" chirps were designed based on previous estimates of cochlear traveling wave speeds (using high-pass subtractive masking methods) in these species. Optimal chirps increased ABR peak amplitudes by compensating for cochlear dispersion; however, chirps with similar (or higher) frequency-modulation rates produced comparable results. The optimal chirps generally increased ABR amplitudes relative to noisebursts as threshold was approached, although this was more obvious when sound pressure level was used to equate stimulus levels (as opposed to total energy). Chirps provided progressively less ABR amplitude gain (relative to noisebursts) as stimulus level increased and produced smaller ABRs at the highest levels tested in dolphins. Although it was previously hypothesized that chirps would provide larger gains in sea lions than dolphins-due to the lower traveling wave speed in the former-no such pattern was observed.

Number of the Most Abundant Marine Mammals Species in the Vicinities of the Antarctic Peninsula, Scotia Sea, and Powell Basin

Number of the Most Abundant Marine Mammals Species in the Vicinities of the Antarctic Peninsula, Scotia Sea, and Powell Basin

Alternative and legacy flame retardants in marine mammals from three northern ocean regions

Flame retardants are globally distributed contaminants that have been linked to negative health effects in humans and wildlife. As top predators, marine mammals bioaccumulate flame retardants and other contaminants in their tissues which is one of many human-imposed factors threatening population health. While some flame retardants, such as the polybrominated diphenyl ethers (PBDE), have been banned because of known toxicity and environmental persistence, limited data exist on the presence and distribution of current-use alternative flame retardants in marine mammals from many industrialized and remote regions of the world. Therefore, this study measured 44 legacy and alternative flame retardants in nine marine mammal species from three ocean regions: the Northwest Atlantic, the Arctic, and the Baltic allowing for regional, species, age, body condition, temporal, and tissue comparisons to help understand global patterns. PBDE concentrations were 100–1000 times higher than the alternative brominated flame retardants (altBFRs) and Dechloranes. 2,2′,4,5,5′-pentabromobiphenyl (BB-101) and hexabromobenzene (HBBZ) were the predominant altBFRs, while Dechlorane-602 was the predominant Dechlorane. This manuscript also reports only the second detection of hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO) in marine mammals. The NW Atlantic had the highest PBDE concentrations followed by the Baltic and Arctic which reflects greater historical use of PBDEs in North America compared to Europe and greater industrialization of North America and Baltic countries compared to the Arctic. Regional patterns for other compounds were more complicated, and there were significant interactions among species, regions, body condition and age class. Lipid-normalized PBDE concentrations in harbor seal liver and blubber were similar, but HBBZ and many Dechloranes had higher concentrations in liver, indicating factors other than lipid dynamics affect the distribution of these compounds. The health implications of contamination by this mixture of compounds are of concern and require further research.

A Review of Circumpolar Arctic Marine Mammal Health-A Call to Action in a Time of Rapid Environmental Change.

The impacts of climate change on the health of marine mammals are increasingly being recognised. Given the rapid rate of environmental change in the Arctic, the potential ramifications on the health of marine mammals in this region are a particular concern. There are eleven endemic Arctic marine mammal species (AMMs) comprising three cetaceans, seven pinnipeds, and the polar bear (Ursus maritimus). All of these species are dependent on sea ice for survival, particularly those requiring ice for breeding. As air and water temperatures increase, additional species previously non-resident in Arctic waters are extending their ranges northward, leading to greater species overlaps and a concomitant increased risk of disease transmission. In this study, we review the literature documenting disease presence in Arctic marine mammals to understand the current causes of morbidity and mortality in these species and forecast future disease issues. Our review highlights potential pathogen occurrence in a changing Arctic environment, discussing surveillance methods for 35 specific pathogens, identifying risk factors associated with these diseases, as well as making recommendations for future monitoring for emerging pathogens. Several of the pathogens discussed have the potential to cause unusual mortality events in AMMs. Brucella, morbillivirus, influenza A virus, and Toxoplasma gondii are all of concern, particularly with the relative naivety of the immune systems of endemic Arctic species. There is a clear need for increased surveillance to understand baseline disease levels and address the gravity of the predicted impacts of climate change on marine mammal species.

Mercury accumulation, biomagnification, and relationships to δ13C, δ15N and δ34S of fishes and marine mammals in a coastal Arctic marine food web

Combining mercury and stable isotope data sets of consumers facilitates the quantification of whether contaminant variation in predators is due to diet, habitat use and/or environmental factors. We investigated inter-species variation in total Hg (THg) concentrations, trophic magnification slope between δ15N and THg, and relationships of THg with δ13C and δ34S in 15 fish and four marine mammal species (249 individuals in total) in coastal Arctic waters. Median THg concentration in muscle varied between species ranging from 0.08 ± 0.04 μg g−1 dw in capelin to 3.10 ± 0.80 μg g−1 dw in beluga whales. Both δ15N (r2 = 0.26) and δ34S (r2 = 0.19) best explained variation in log-THg across consumers. Higher THg concentrations occurred in higher trophic level species that consumed more pelagic-associated prey than consumers that rely on the benthic microbial-based food web. Our study illustrates the importance of using a multi-isotopic approach that includes δ34S when investigating trophic Hg dynamics in coastal marine systems.

A Novel Marine Mammal Coxiella burnetii-Genome Sequencing Identifies a New Genotype with Potential Virulence.

The obligate intracellular bacterial pathogen Coxiella burnetii has been identified in a few species of marine mammals, some of which are showing population declines. It has been hypothesized that C. burnetii in marine mammals is a distinct genotype that varies significantly from the typical terrestrial genotypes. It appears to lack an IS1111. Isolates originating from Australian marine animals have a distinctly non-Australian profile of multiple-locus variable-number tandem-repeat analysis (MLVA). Extracted Coxiella DNA of Australian fur seal placental origin was sequenced using the Novaseq platform. Illumina 150 bp paired-end reads were filtered and trimmed with Trimgalore. The microbial community present in the sequenced genome was evaluated with Kraken and Bracken software using the NCBI database. A phylogenetic analysis was performed using 1131 core genes. Core genes were identified using Panaroo and inputted into Iqtree to determine the maximum-likelihood tree. A second phylogenetic tree was created using Rickettsiella grylii and using seven housekeeping genes. Results were compared with the C. burnetii Nine Mile RSA439 virulent genome. This new Australian marine mammal isolate of Coxiella (PG457) appears to be a novel genotype that lacks IS1111 and has a distinct MLVA signature (ms26, ms27, ms28, ms30, and ms31). The presence of genes for multiple virulence factors appears to give this genotype sufficient pathogenicity for it to be considered a possible causative agent of abortion in Australian fur seals as well as a potential zoonotic risk.

Synthesizing connectivity information from migratory marine species for area-based management

Understanding the areas used by migratory marine animals and their movements is critical in supporting management decisions that target their conservation. This is especially important for long-lived species with large geographic extents and are more vulnerable to multiple threats. We conducted a literature review on data collected for 173 marine mammal, marine fish, sea turtle, and seabird species and determined that tracking animal movements with telemetry methods was the most effective tool for demonstrating ecological connectivity. From the references included for review, we found more references for sea turtles than other taxa, and more information was collected for all four taxa in the northern hemisphere. In addition, 30 % of references presented methods to process the raw telemetry tracks, only 11 % of references mentioned a repository for archiving data, and there was no significant trend in the number of references and current conservation level. For four case study species (Atlantic bluefin tuna, humpback whale, loggerhead sea turtle, and wandering albatross), we found more information published for adults and on the descriptions of sites focused on feeding and breeding activities, while sites used for migration and connectivity among areas used for migration were not well represented. Although connectivity data were published for most of the migratory marine species we reviewed, several knowledge gaps existed and there were limitations of the data presented within publications for direct applications to area-based management. We provided recommendations to address research gaps and guidance to improve the integration of connectivity data into area-based management decisions.

High aluminum content in bone of marine mammals and its relation with source levels and origin

Although aluminum is widely distributed in the earth's crust, its environmental availability and wildlife assimilation rates are only partially known. Here we analyze aluminum concentrations in bone from 10 species of marine mammals inhabiting 3 geographic areas subject to different aluminum inputs: the Río de la Plata estuary (Uruguay), the coastal waters of Mauritania and the Galapagos archipelago (Ecuador). Overall, concentrations were unusually high as compared to those of terrestrial animals, with lowest concentrations in the Galapagos archipelago, then the Río de la Plata estuary and finally Mauritania. The aluminum source varied between regions, prevailing anthropogenic sources in the Río de la Plata Estuary and natural sources (wind-blown dust) in Mauritanian waters. The type of source determined contamination levels: anthropogenic sources were most significant for coastal species and showed a decline with distance of habitat from shoreline, while natural sources had a higher influence on open waters because of the dearth of biogenic silica that eliminates aluminum from the water column. Since aluminum remains in bone for several decades, marine mammal bone reflects historical levels of aluminum and therefore is a good bioindicator of the aluminum concentration of the marine environment.

Nutrient inputs from subarctic rivers into Hudson Bay

Hudson Bay (HB), a large subarctic inland sea, is impacted by rapid climate change and anthropogenic disturbance. HB plays crucial roles in supporting resident and migratory species of birds and marine mammals, providing subsistence to coastal communities, and exporting nutrients into the western Labrador Sea. To better constrain the impact of river nutrients on the HB ecosystem and to obtain a contemporary reference point by which future change can be evaluated, we estimated fluxes of nitrate plus nitrite (N), phosphate (P), and silicate using contemporary and historical nutrient data in conjunction with discharge estimates produced by three global climate models. Concentrations and molar ratios of the different nutrients exhibited large contrasts between different sectors of HB, which is attributed to the diversity of geological settings across distinct watersheds. With respect to the needs of primary producers, river waters were characterized by a shortage of P during winter and spring (N:P molar ratios in dissolved nutrients >16), nearly balanced N:P ratios in summer, and a shortage of N during fall (N:P < 16). Southwestern rivers made the largest regional contribution to the total annual delivery of all nutrients, followed by modest contributions from southern and eastern rivers, and minor ones from northwestern rivers. While the regulation of river flow in the Nelson and La Grande rivers had no discernible impact on nutrient concentrations and ratios, it clearly shifted nutrient transports toward the winter when biological activity in the estuaries is reduced. Finally, the potential amount of new production supported by riverine N inputs was nearly two orders of magnitude (1.8 × 1011 g C yr−1) lower than the new production supported by marine nutrients (7.3 × 1012 g C yr−1). Although the potential contribution of river nutrients to new primary production is small (2.4%) at the bay-wide scale, it can be significant locally.

Modeling the acoustic noise from a wave energy converter farm and its impact on marine mammals at the PacWave South site, offshore Newport Oregon

Marine hydrokinetic devices, such as wave energy converters (WECs), can unlock untapped energy from the ocean's currents and waves. Acoustic impact assessments are required to ensure that the noise these devices generate will not negatively impact marine life, and accurate modeling of noise provides an a priori means to viably perform this assessment. We present a case study of the PacWave South site, a WEC testing site off the coast of Newport, Oregon, demonstrating the use of ParAcousti, an open-source hydroacoustic propagator tool, to model noise from an array of 28 WECs in a 3-dimensional (3-D) realistic marine environment. Sound pressure levels are computed from the modeled 3-D grid of pressure over time, which we use to predict marine mammal acoustic impact metrics (AIMs). We combine two AIMs, signal to noise ratio and sensation level, into a new metric, the effective signal level (ESL), which is a function of propagated sound, background noise levels, and hearing thresholds for marine species and is evaluated across 1/3 octave frequency intervals. The ESL model can be used to predict and quantify the potential impact of an anthropogenic signal on the health and behavior of a marine mammal species throughout the 3-D simulation area.

Marine protected areas in the southern south‐west Atlantic: Insights from marine top predator communities

AbstractThe marine ecosystem provides numerous goods and services, dampens the impacts of floods and storms, and provides climate control, through the regulation of carbon fluxes, nutrient cycling, and the bioremediation of human waste and tourism. However, the ocean is vulnerable to anthropogenic threats and has been severely altered by humans.Seabirds and marine mammals are long lived, highly mobile, easily identifiable, and occupy the upper levels of trophic webs. These ecological features make them suitable as sentinels of the marine ecosystem.Sighting data collected during eight oceanographic surveys were analysed to describe and compare the biodiversity of the communities of top predators within the marine protected areas (MPAs) of Namuncurá/Burdwood Bank I and II and the surrounding areas in two contrasting seasons (summer and winter). Data were grouped into six zones based on depth and geographic position.Twenty‐five species of seabirds and 13 species of marine mammals were recorded in 113 days of surveys between 2014 and 2018. Top predator community composition varied seasonally in the different zones.A suite of indicator species was identified according to their specificity and fidelity to a particular zone. Most of the species identified as potentially useful indicators differed between summer and winter, highlighting the importance of conducting systematic surveys in both periods.The MPAs Namuncurá/Burdwood Bank I and II are key areas for top predator communities in the region, mainly in summer when the number and abundance of species increase. However, the waters around Isla de los Estados and the channel between Isla de los Estados and Burdwood Bank were also identified as a relevant habitat for many species. This knowledge should be included to create a regional network of areas under special management considerations that connect the established MPAs with other key pelagic and coastal areas (as found in this study) for the conservation of subantarctic marine megafauna.